In this paper, the methods of wavelet transform, correlation analysis, and harmonic analysis were used to analyze the variation characteristics of Xianyou well water level in each frequency band before and after being disturbed by well drilling and pumping in July 2017. The results showed that the serious well drilling and pumping disturbance has a significant influence on the full frequency of water level. After the interference tends to be stable, the intermediate frequency band basically recovers, but there are still many strong signals in the low frequency band, and the response capacity of M₂ tidal strain is slightly decreased, indicating that the intermediate frequency band of Xianyou well water level is an effective monitoring band for stress change after being disturbed. The research methods and results of this paper can provide reference for interference analysis and anomaly extraction of water level data.